Method for processing an animal carcass and apparatus for providing electrical stimulation

ABSTRACT

Apparatus and method for processing animal carcasses are described. The method for processing the animal carcass includes electrically stimulating a target region of the animal carcass. By focusing or concentrating electrical stimulation on the middle muscle portion of an animal carcass, the middle muscle portion of the animal carcass can be tenderized without substantially interfering with the cooling rate of the muscles provided in the anterior and posterior portions. The apparatus includes an electrical stimulation frame that includes a plurality of electrical stimulation probes, an upper ground, and a lower ground, which are constructed and arranged for focusing or concentrating electrical stimulation on the middle muscles of an animal carcass.

RELATED APPLICATION

This application claims priority to U.S. provisional patent applicationNo. 60/132,051 that was filed on Apr. 30, 1999. The entire disclosure onU.S. provisional application No. 60/132,051 is incorporated herein byreference.

FIELD OF THE INVENTION

The invention relates to a method for processing an animal carcass andan apparatus for providing electrical stimulation during the slaughterprocess. More particularly, the invention is directed to a method andapparatus for concentrating or focusing an electrical stimulation to aspecific portion of an animal carcass.

BACKGROUND OF THE INVENTION

Electrical stimulation is one of a variety of methods, which have beenused for at least the past twenty-five years to tenderize meat products.Electrical stimulation results in an acceleration of rigor mortis and acorresponding more rapid decrease of pH in the meat. Electricalstimulation influences the progress of post mortem biochemical processesin the muscle tissue of the slaughtered animal.

When an animal is alive, the muscle tissue operates under a conditionthat is called aerobic metabolism, which simply means that oxygen isavailable to the muscle tissue. When an animal dies, the muscle tissuegoes into a state called anaerobic metabolism wherein oxygen is notavailable to the muscle tissue. Aerobic metabolism involves a processwherein the muscles utilize the sugar/glucose and burns it in order tocreate energy for use in relaxation and contraction of the muscles. Theenergy resulting from the sugar/glucose used by muscles in relaxationand contraction is further converted into water and carbon dioxide aslong as the animal is breathing and oxygen is being received into thebody. The water and carbon dioxide exits the body as waste. Underanaerobic metabolism conditions, the muscles utilize sugar/glucose tocreate energy for use in relaxation and contraction of muscles. Underanaerobic conditions, contractions occur by applying electricalstimulation to the carcass, and relaxation of muscles results fromremoval of the electrical stimulation. The energy used during musclecontraction and relaxation under anaerobic conditions is not furtherconverted into water and carbon dioxide that exits the body as waste.That energy is shunted off as lactic acid, carrying a correspondingdecline in muscle pH.

During anaerobic metabolism conditions, there is a gradual build up oflactic acid, resulting from the contraction and relaxation of musclesthat causes the pH in the muscle to shift. Normal pH in living muscletissue is about 7. As the typical onset of rigor mortis occurs and thereis a build up of lactic acid, there is a shift in pH from about 7 downto about the 5.6 to 5.8 range. As long as there is sugar/glucose in themuscle tissue of the body that can be used as energy, the muscle will gothrough relaxation and contraction. When the sugar/glucose is depleted,the filaments present in the muscle tissue become fixed and rigid, thusthe term “rigor mortis” refers to stiffening of the muscles after death.

Electrical stimulation of muscles accelerates the process of rigormortis because electrical stimulation of the muscles causes severecontractions. The contractions in the muscles result in the musclesusing up the sugar/glucose energy in the muscles faster. Accordingly,the muscle tissue goes into rigor mortis faster.

Prior art literature teaches that the effects of electrical stimulationworks best on slaughtered animals when the nerve tracks of the animalstill have the possibility to transfer stimulation. Some prior artmethods teach that electrical stimulation has the best effect shortlyafter death. Other prior art methodologies, such as that disclosed inU.S. Pat. No. 4,561,149, teach that the electric current should beapplied to the animal while it is still alive during at least part ofthe time period following complete stunning of the animal where therehas been a complete lost of consciousness, and prior to the clinicaldeath of the animal.

In the prior art methods of applying electrical stimulation toslaughtered animals, electrical stimulation can involve the use ofdirect current or alternating current, voltages that range between20-3,600 volts, frequencies that range between 0-60 Hertz, and currentsranging between 0.1-6 amperes. Prior art literature indicates that thelater after clinical death the application of electrical stimulation,the more current needs to be applied.

It is believed that the cooling of meat prior to the completion of rigormortis causes the muscles of the slaughtered animal to contract. Thecontracting of the muscles causes the meat to be tough. In some cases,contracting or shortening of the muscle tissue may be up to as much as50%. On the other hand, if the meat of the carcass is not cooled to atleast a minimum level, around 65 degrees, prior to the completion ofrigor mortis, other problems with the meat will result. One such problemis a condition called pale soft exudative (PSE), which causes theslaughtered meat to be pale in color, soft and watery. PSE results whenthe meat temperature is too high when the muscle enters rigor mortis. Asthe meat continues to cool and finally cools to the desired level, itwill have a tendency to lose moisture content, be pale in color and besofter than normal.

Most generally, the prior art devices, which apply electricalstimulation to an animal carcass, apply the electrical charge throughthe entire carcass. An example of such a device and of the conventionalmethod of applying an electrical stimulus to the entire animal carcassis disclosed in U.S. Pat. No. 2,544,861 to Harshan et al. It has beenfound that using an apparatus such as the disclosed U.S. Pat. No.2,544,861 to Harshan et al. results in the denser thicker muscledsections of the carcass having PSE tendencies. This results when usingan apparatus that applies an electrical stimulus to the entire animalcarcass, such as the disclosed in U.S. Pat. No. 2,544,861 to Harshan etal., because the thick muscled sections of the carcass, such as theround and chuck muscles cannot be chilled at the same rate as the lessdense loin and rib portions. The inability of the denser meat portionsof the carcass to chill as rapidly as the less dense portions, in someinstances, provides circumstances for rigor mortis to occur prior tosufficient chilling of the denser meat portions resulting in the denserchuck and round meat portions having the undesirable characteristics ofbeing pale colored, soft and watery.

There is a need for an apparatus and method that allows for the use ofelectrical stimulation of an animal carcass to improve tenderness and toaccelerate the completion of rigor mortis in the fabrication process ofan animal carcass, wherein the apparatus and method take the varyingdensities of the meat portions into consideration.

SUMMARY OF THE INVENTION

Methods and apparatus for electrically stimulating animal carcasses areprovided by the invention. The methods include electrically stimulatinga target region or area of an animal carcass relative to other regionsor areas of the animal carcass. In particular, the targeted regionincludes the midsection of an animal carcass which generally has thinnermuscles compared with the posterior and anterior ends of an animalcarcass. Preferred animal carcasses that can be processed according tothe invention include bovine carcasses, such as, bull, heifer, cow, andsteer carcasses. Additional animal carcasses that can be processedaccording to the invention include porcine, ovine, and poultrycarcasses.

It is generally desirable to cool the internal muscle temperature of ananimal carcass prior to the onset of rigor. The applicants have foundthat electrical stimulation generates heat within the muscle tissuebeing electrically stimulated. In order to allow the thicker musclesprovided in the posterior and anterior regions of an animal carcass tocool prior to the onset of rigor, the applicants have developed atechnique for focusing or concentrating electrical stimulation withinthe midsection of an animal carcass, and, in general, isolating theposterior and anterior regions of the animal carcass from electricalstimulation. Because the regions of the animal carcass (anterior,midsection, and posterior) are not split apart during the step ofelectrical stimulation, it is expected that the posterior and theanterior regions will receive some level of electrical stimulation butsubstantially less electrical stimulation than the midsection of theanimal carcass.

The electrical stimulation apparatus includes an electrical stimulationframe having an inlet, an outlet, and a length extending between theinlet and the outlet. The frame is constructed for allowing an animalcarcass to pass from the inlet to the outlet and for providing targetedelectrical stimulation to the animal carcass as it passes from the inletto the outlet. The electrical stimulation frame includes a plurality ofelectrical stimulation probes, an upper ground, and a lower ground. Theplurality of electrical stimulation probes is provided along the lengthof the frame for contacting the animal carcass as it passes between theinlet and the outlet. The upper ground is provided extending along thelength of the frame above the plurality of electrical stimulation probesand is provided for contacting the animal carcass. The lower ground isprovided extending along the length of the frame and below the pluralityof electrical stimulation probes and is provided for contacting theanimal carcass. In general, it is desirable for the upper ground and thelower ground to contact the animal carcass while the animal carcass isbeing electrically stimulated by at least one of the plurality ofelectrical stimulation probes. If the animal carcass is not grounded toeither or both of the upper ground and the lower ground, it is expectedthat the animal carcass will ground through the trolley conveying theanimal carcass. It is desirable to ground the animal carcass throughboth the upper ground or the lower ground to maintain a focus orconcentration of current through the muscles provided in the midsectionof the animal carcass and to minimize electrical stimulation of themuscles provided in the anterior and posterior regions of the carcass.

A method for electrically stimulating an animal carcass is provided bymoving an animal carcass along a length of the electrical stimulationframe from the inlet to the outlet, and electrically stimulating theanimal carcass. Preferably, the animal carcass is moved along theelectrical stimulation frame dorsal side first in order to maximize thecontact of the surface of the animal carcass with the plurality ofelectrical stimulation probes.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become apparent upon consideration of thefollowing detailed description of an embodiment thereof, especially whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a diagrammatic view of a beef carcass being stimulated by theapparatus of the present invention;

FIG. 2 is a perspective view of the electrical stimulation apparatus;

FIG. 3 is a schematic view of the circuitry employed in the electricalstimulation apparatus;

FIG. 4 is a side view of an alternative embodiment of an electricalstimulation apparatus according to the principles of the presentinvention; and

FIG. 5 is a perspective view of the electrical stimulation apparatus ofFIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

A method for processing an animal carcass is provided by the invention.An animal carcass generally refers to the body of an animal after it hasbeen stunned and rendered unconscious. The processing of an animalcarcass is generally an assembly line type operation where severalcarcass are moved and processed along a series of stations. While thefollowing includes a discussion of the processing of a single animalcarcass, it should be understood that the processing of an animalcarcass, according to the present invention, can be applied to acontinuous assembly line operation of processing numerous animalcarcasses.

The slaughter operation generally includes the operations of stunning,bleeding, hide removal and evisceration of the animal and subsequentlycooling the animal carcass to a desired temperature. Typically, adesired internal muscle temperature is about 40° F. or less. Slaughterplants often have chill capabilities of 24 hours or 48 hours. Thoseplants with 24 hour capacity must chill rapidly while plants with 48hour capacity can chill more slowly. The general objective in coolingthe animal carcass is to reduce the internal muscle temperatures of theanimal carcass to below about 70° F. prior to the onset of rigor. Theinternal muscle temperature refers to the temperature deep within aparticular muscle. Ideally, the internal muscle temperature should bereduced to the middle 60s° F. prior to the onset of rigor. Iftemperatures are above this range when rigor mortis completion occurs,PSE muscle may result. The onset of rigor is characterized by stiffeningof the muscles after death. The steps of processing the animal carcass,after it has been cooled to a desired temperature, are generallyreferred to as the fabrication process.

Certain muscles on the animal carcass are thicker than other muscles. Itcan be difficult to sufficiently cool the thick muscles so they reach aninternal muscle temperature of below about 70° C. prior to the onset ofrigor. This is particularly true if the thick muscles have beenelectrically stimulated and rigor consequently accelerated. Theinvention provides for the electrical stimulation of the thinner musclesprovided along the midsection of the animal carcass, withoutsubstantially electrically stimulating the end sections of the animalcarcass. It should be appreciated that the reference to notsubstantially electrically stimulating the end sections of the animalcarcass indicates that the end sections are not targeted for electricalstimulation. Rather, the midsection is targeted for electricalstimulation, and the end section may receive, in view of their proximityto the midsection, a minor amount of electrical stimulation.Accordingly, electrical stimulation is concentrated or focused in themidsection of the animal carcass, and the amount or extent of electricalstimulation in the end sections is expected to be significantly lessthan provided in the midsection. It should be appreciated that thereference to isolating electrical stimulation from the end sections isnot meant to require a complete absence of any electrical stimulation inthe end sections, but rather reflect the understanding that theelectrical stimulation is to be focused or concentrated in themidsection rather than in the end sections.

Various animal carcasses can be processed according to the invention.Preferred animal carcasses include bovine carcasses and moreparticularly, cow or steer carcasses. In a cow or steer carcass, themidsection generally refers to the region which includes the rib sectionand the loin. The anterior portion of the animal carcass, includes theshoulder muscles which industry refers to as the chuck. The posteriorend of the animal carcass includes the hind limb muscles which industryrefers to as the round. More technically, the midsection includesthinner muscles of the rib and loin that are generally characterized asextending from about between the fifth and sixth thoracic vertebrae andabout between the fourth and fifth sacral vertebrae. By focusing theelectrical stimulation on the rib and loin midsection, the electricalcurrent generally remains isolated from the chuck and round muscles.Accordingly, by electrically stimulating the middle muscles, it isexpected that the tenderness of the middle muscle can be enhanced andthe quality of the middle muscle can be enhanced as perceived by theconsumer.

Referring in detail now to the drawings, wherein an embodiment of theinvented method and apparatus for electrically stimulating an isolatedarea of a livestock carcass is shown. The livestock carcass 10 is abovine carcass. The apparatus, shown in FIGS. 1 and 2, referred to as100 in FIG. 1, which provides for the electrical stimulation of anisolated section of the carcass 132, includes a housing 101, anelectrical stimulation stake 118 and a pair of ground stakes 114 and116. The electrical stimulation stake 118 is electrically connected tothe housing by wire 120. The ground stakes 114 and 116 are electricallyconnected to the housing 101 by wires 122 and 124. The housing 101further includes first and second push activated safety interlockbuttons 102 and 104, an electrical stimulation duration indication light106, a pulse indication light, a voltmeter 110 and an ammeter 112.

The apparatus 100 performs the method of electrically stimulating anisolated area of a livestock carcass by inserting the electricalstimulation stake 118 and the pair of ground stakes 114 and 116 into thecarcass 10 in the manner shown. The animal carcass 10 has a midsection20 including relatively thin muscles 22. Exemplary thin muscles in themidsection 20 include the loin 24 and the rib muscle 26. The animalcarcass 10 additionally includes an anterior end 28 and a posterior end30. The anterior end 28 includes chuck muscle 32, and the posterior end30 include round muscle 34. In many bovine carcasses, the chuck andround muscles are as much as twice as thick as the loin and rib muscles.Accordingly, reducing the internal muscle temperature of the chuck andround muscles is often a much slower process compared with reducing theinternal muscle temperature of the loin and rib muscles. Attaching theelectrical stimulation stake 118 and the pair of ground stakes 114 and116 into the carcass 10 as shown generally results in the substantialisolation of the round and chuck muscles of the carcass from electricalstimulation during operation of the apparatus 100.

More specifically, the first ground stake 114 is preferably insertedinto the carcass in the vicinity of the fourth or fifth sacralvertebrae. The first ground stake 114 is inserted into this area of thecarcass because this area is the separation point of the carcass loinand round sections. The second ground stake 116 is preferably insertedinto the carcass in the vicinity of the fifth and sixth thoracicvertebrae. The second ground stake 116 is inserted into this area of thecarcass because this area is the separation point of the carcass rib andchuck. The electrical stimulation stake 118 is preferably inserted intothe carcass in the vicinity of the fourth and fifth lumbar vertebrae.The electrical stimulation stake 118 is preferably inserted into thisarea of the carcass because this area is the separation point of the toploin and sirloin portions of the loin.

During operation of the apparatus 100 that performs the method ofelectrically stimulating an isolated area of the livestock carcass 10,current flows from the electrical stimulation stake 118 through the loinsection of the carcass to first ground stake 114 and flows from theelectrical stimulation stake 118 through the loin section of the carcassto second ground stake 116. Current flow through the loin section of thecarcass causes the muscles in the carcass to go through relaxation andcontraction, thereby causing an acceleration of the rigor mortis andfaster decrease of pH in the carcass meat. Substantial isolation ofcurrent flow through the loin section of the carcass provides for fasterrigor mortis in the loin section. Any electrical stimulation applied tothe round and chuck areas of the carcass 10 is marginal.

Referring to FIG. 2, the apparatus 200 that provides for the electricalstimulation of an isolated section of an animal carcass is shown.Generally, the apparatus includes a housing 201, and three stimulationstakes 214, 216 and 218, which provide for the substantial isolation ofelectric current flowing through a defined area of the carcass. Thedefined area of current flow through the carcass is outlined generallyby the positioning of the stimulation stakes 214, 216 and 218 in amanner substantially similar to insertion of stimulation stakes 114,116, and 118 into the animal carcass 10 as illustrated in FIG. 1.Stimulation stake 218 is electrically connected to the housing 201 by awire 220. Stimulation stake 218 is sometimes referred to as the hotstimulation stake because it is the stimulation stake with the highelectrical potential relative to ground. Stimulation stakes 214 and 216are referred to as the ground stakes because these stimulation stakeswhich are electrically connected to the apparatus housing 201 by wires222 and 224 and have zero potential. The housing 201 further includes 2push-activated safety interlock buttons 202 and 204 which both need tobe engaged or pressed in order to begin the cycle of electricalstimulation. The dual push activity safety interlock buttons 202 and 204are necessary in order to provide safety to an operator of the apparatusso that the operator has less of a chance to inadvertently touch thecarcass with a free hand during the electrical stimulation portion ofthe fabrication process. In addition, the housing includes a volt meter210 and an amp meter 212. A voltmeter 210 and amp meter 212 areinstalled on the apparatus in order to provide user feedback duringparameter variation. The apparatus 200 provides for the variation ofcurrent and voltage potential on the hot stimulation stake 218.

More specifically, the present embodiment of the apparatus for applyingelectrical stimulation to an isolated section of a carcass has avariable voltage output of 0-600 volts. The voltmeter 210 illustratesthe voltage applied through the hot stake 218. The voltage and currentapplied to the hot stake 218 are variable in the present embodimentbecause of the relationship voltage equals current multiplied by theresistance (V=R*I). For example, in the illustration shown in FIG. 1,wherein the apparatus for applying electrical stimulation to an isolatedsection of a carcass is utilized on a beef carcass, because theresistance on a beef carcass is approximately 90 ohms, in order toachieve different levels and types of electrical stimulation, thevoltage and current must be varied. Modifications may include adjustingthe shock duration, and pulse intervals of the electrical stimulationbeing applied. The stimulation stakes 114, 116 and 118 are comprised ofsharpened aluminum stakes with handles 230, 232 and 234. The handles230, 232 and 234 are not electrically isolated. The dual push-activatedsafety interlock button system requiring an operator to use both handsto press the interlock buttons before the system can only be activatedprovides safety from human touch. Accordingly, the operator will not beable to handle the stimulation stakes 214, 216 and 218 when the power isapplied to the apparatus 200.

The circuit housed in apparatus 200 is illustrated in FIG. 3. Thiscontrol unit has a main power on switch 352 which may be moved betweenoff 354 and on 356 positions whenever it is desired to operate theapparatus for electrically stimulating an isolated area of a livestockcarcass. Movement of the main power on switch 352 from the off position354 to the on position 356 supplies 110 volts to the circuit 300. The110 volts is directed through a 30-amp circuit breaker that allows fordisabling of current through the circuit 300 when current exceeds 30amps. Once the on/off switch 352 is turned to the on position 356, thecircuit recognizes that voltage is being applied at node 356 through thepower on indication lamp 360. In order for power to be applied to theremainder of the circuit, both buttons 302 and 304 of the dual buttonpush activated safety interlock switch must be engaged. The dual buttonpush activated safety interlock switch provides a safety mechanism sothat the system operator has to have both hands on the apparatus inorder for power to be applied to the circuit. If the operator were todisengage either of the two buttons 302 and 304 of the dual button pushactivated safety interlock switch, the 110 volts would be isolated fromthe remainder of the circuit 300, disengaging the apparatus forelectrically stimulating an isolated area of a livestock carcass. Uponpressing both push activated safety interlock buttons 302 and 304, aclosed circuit occurs and power is applied to switch timer T1, 362. Whenpower is applied to switch timer T1, 362, the switch portion closes 358and the timer begins to count through its timing sequence. Switch timerT1 is a variable timer. Accordingly, it is to be understood that thetiming sequence that switch timer T1 controls is variable and can be seta length desired by the system user. For example, if switch timer T1 362has a timing sequence of one minute, the switch portion of switch timerT1 358 will remain closed for one minute, unless the operator disengagesone or both of the buttons 302 and 304 of the dual button push activatedsafety interlock switch. If either or both buttons 302 and 304 aredisengaged, timer T1 362 will automatically reset and the time durationcycle begins again. Assuming the operator maintains engagement of bothbuttons 302 and 304 of the dual button push activated safety interlockswitch, the switch portion 358 of timer T1 remains closed for the timeduration set and automatically opens after the preset time duration oftimer T1 cycles through. The automatic opening of the switch portion 358of timer T1 eliminates the need for the operator to time the applicationof electrical stimulation to the carcass. The electrical stimulationapplication time duration is automatic. The operator is notified thatelectrical stimulation is complete because the electrical stimulationduration light 306 would no longer be illuminated.

During the timing sequence, when the switch portion of switch timer T1has a closed circuit 358, power is applied to switch timer T2 364, 368.Switch timer T2 364 is a pulse timer that controls the pulsing functionof the electrical stimulation being applied through activation ofcontrol relay CR3 384. Switch Timer T1 also activates control relay C2366 that controls application of voltage to the transformer 340. Controlrelay C2 366, 378, 380 is a power activated switch which closes circuitconnections 370 and 380 when switch timer T1 358 allows voltage to beapplied to control relay C2, 366. Upon the activation of the switches378 and 380 of control relay C2, the transformer 340 may be energized.

Energizing control relay C2 applies voltage to the stimulation durationlamp 306 and the variac 374 that are electrically connected to thetransformer 340. The variac 374 provides a means for control of theoutput voltage applied to the transformer 340 to be stepped up. In thepresent embodiment, the variac 374 can apply a variation of voltages,from 0-120 volts AC, to the transformer 340. That variable voltage isapplied to the step-up transformer 340 wherein the voltage may bestepped up from 120 to 600 volts AC if the variac is applying 120 voltsto the transformer. The voltmeter 372 measures the voltage output by thestep up transformer 340 and provides the system operator with a visualindication of the voltage being applied to the carcass.

Circuit 300 also illustrates that electrical stimulation stake 318 andthe ground stakes 314 and 316. The ground stakes 314 and 316 areelectrically connected to ground. The electrical stimulation stake 318is electrically connected to the circuit 300 through control relay C3,370. Control relay C3, 370 is energized upon activation of pulse timerT2, 364 causing the switch portion of switch timer T2, 368 to close. Thetiming on switch timer T2, 364, while variable, in the preferredembodiment it is approximately 2 seconds. Accordingly, the switch 368portion of pulse timer T2 cycles through open and close positions every2 seconds during the timing sequence of switch timer T1, 362. Whenswitch timer T1 362 completes its timing sequence, the switch portion358 of timer T1 opens, disabling energization of the variac 374 andtransformer 340 portions of the circuit. When timer T2 368 closes, theswitch portion 368 in this embodiment for two seconds, control relayCR3, 370, is energized and the switch portion of control relay CR3, 384is closed and the voltage from the transformer 340 is applied to theelectrical stimulation hot stake 318 through the electrical connection320. The ammeter 382, also displays the current applied to theelectrical stimulation stake 318 so that the operator can monitor thecurrent being applied to the carcass. It is to be understood that thetiming sequences in timers T1 and T2 are variable.

Now referring to FIGS. 4 and 5, an alternative embodiment of anelectrical stimulation apparatus according to the present invention isshown at reference numeral 400. The electrical stimulation apparatus 400is particularly adapted for application to a continuous assembly lineoperation for processing animal carcasses.

Animal carcasses, such as, bovine carcasses, are commonly split toprovide a left side and a right side. The split is usually providedalong the backbone. According to the invention, the reference to “animalcarcass” is meant to describe whole carcasses, half carcasses, and anyother subdivision of an animal carcass. As described in more detailbelow, an animal carcass which can be processed according to theinvention is either a left side carcass or a right side carcass, whereinthe whole animal carcass has been split down its backbone to create theleft side carcass and the right side carcass. Additional carcasses thatcan be processed according to the invention include porcine carcasses,ovine carcasses, and poultry carcasses.

During processing, the animal carcass sides can be hung from theposterior portion of the side from a hanger 402. The hanger 402 can beconsidered part of a conveyor 403 that conveys an animal carcass (eitherwhole or side) through animal processing operations. The hanger 402 canbe provided in the form of a hook 404. The hanger 402 extends from atrolley 406 that runs along a rail 408. The trolley 406 can be pulledalong the rail 408 by a chain 409.

The electrical stimulation apparatus 400 can be used to provide targetedelectrical stimulation to an animal carcass. The animal carcass 410 isshown as a right side carcass and moves through the electricalstimulation frame 412 in the direction of the arrow. Moving in thedirection shown, the animal carcass 410 enters the electricalstimulation frame 412 at the inlet 414 and exits at the outlet 416. Theelectrical stimulation apparatus 400 can be constructed so that as theanimal carcass 410 moves through the length 418 of the electricalstimulation frame 412 between the inlet 414 and the outlet 416, itreceives the desired electrical stimulation protocol.

The electrical stimulation frame 412 includes a left side frame 420 anda right side frame 422. It should be appreciated that the electricalstimulation frame 412 can be provided with either the left side frame420 or the right side frame 422. It is a matter of convenience toprovide both the left side frame 420 and the right side frame 422 inorder to accommodate convenient processing of either side of an animalcarcass. The animal carcass 410 moves from the inlet 414 to the outlet416 along an animal carcass traveling path 423 provided between the leftside frame 420 and the right side frame 422.

The left side frame 420 includes an upper ground 424, a lower ground426, and a plurality of electrical stimulation probes 428 providedbetween the upper ground 424 and the lower ground 426. Similarly, theright side frame 422 includes an upper ground 430, a lower ground 432,and a plurality of electrical stimulation probes 434 provided betweenthe upper ground 430 and the lower ground 432. It should be appreciatedthat the reference to “upper” and “lower” refers to the respectivelocation of the ground relative to the electrical stimulation probes.That is, as the animal carcass is suspended from a hanger 402, the uppergrounds 424 and 430 are provided closer to the hanger 402 than theplurality of electrical stimulation probes 428 and 434, and the lowergrounds 426 and 432. Furthermore, although the upper ground 424 and thelower ground 426 are shown provided within a vertically extending plane,this condition is not necessary. That is, the upper ground 424 and thelower ground 426 are provided so that they contact the animal carcass410 as it moves along the animal carcass traveling path 423. In order tomaintain contact between the upper ground and the carcass or between thelower ground and the carcass, it may be appropriate to extend either orboth of the upper ground or the lower ground further into the animalcarcass traveling path. The upper grounds 424 and 430, lower grounds 426and 432, and plurality of electrical stimulation probes 428 and 434 aresupported by left and right frame constructions 433 and 435.

In a typical animal processing facility, an animal carcass is suspendedfrom its posterior end so that its anterior end is closer to the ground.Accordingly, the position of each of the upper grounds 424 and 430, thelower grounds 426 and 432, and the plurality of electrical stimulationprobes 428 and 434 can be arranged based upon the expected position ofthe muscle of an animal carcass passing along the animal carcasstraveling path 423. For example, it is desirable for the electricalstimulation probes 428 and 434 to be placed so that they contact theanimal carcass surface about centrally to the muscles targeted forelectrical stimulation. In addition, it is generally desirable for theupper grounds 424 and 430 to contact the surface of the animal carcassat a location which allows for electrical stimulation in the midsectionbut minimizes electrical stimulation within the muscles in the posteriorregion. In general, this location can correspond to a location at aboutthe border between the midsection and the posterior end section of theanimal carcass. Similarly, it is generally desirable for the lowergrounds 426 and 432 to contact the animal carcass surface at a locationthat allows for electrical stimulation in the midsection but minimizeselectrical stimulation within the muscles in the anterior region. Ingeneral, this location can correspond to a location at about thejunction between the midsection and the anterior region of an animalcarcass. In a preferred embodiment, the electrical stimulation probescontact the surface of the animal carcass at a location corresponding tothe region of the fourth and fifth sacral vertebrae, the upper grounds424 and 430 contact the surface of the animal carcass at a locationcorresponding to between about the eleventh thoracic vertebrae and thesecond lumbar vertebrae, and the lower grounds 426 and 432 contact thesurface of the animal carcass at a location corresponding to about thefifth thoracic vertebrae and the sixth thoracic vertebra. In thesituation where bovine carcasses are being processed, the verticaldistance between the plurality of electrical stimulation probes and theupper ground is between about one foot and about two feet, and thedistance between the plurality of electrical stimulation probes and thelower ground is between about one foot and about two feet. Preferably,the distance between the electrical stimulation probes and the upperground and the lower is about one and one-half feet.

It should be appreciated that the electrical stimulation probesaccording to the invention are used in combination with the ground togenerate an electric current in targeted muscles. Accordingly, theelectrical stimulation probes include a surface that contacts the animalcarcass. In the case of electrical stimulation probes that are stakes,the stakes are embedded into the carcass (preferably muscle).Preferably, the electrical stimulation probes provide surface contactwith the surface of the carcass, and are not inserted into the muscle ofthe carcass.

When the electrical stimulation frame 412 includes both a left sideframe 420 and a right side frame 422, it is desirable to provide a space440 between the frames which is sized to receive the animal carcass 410while allowing the upper grounds 424 and 430 and the lower grounds 426and 432 to contact the animal carcass 410. When processing bovinecarcasses, it is preferable to provide a distance between the uppergrounds 424 and 430 of between about one foot and about five feet, and adistance between the lower grounds 426 and 432 of between about one footand about five feet. Preferably, the distance between the upper groundsand the distance between the lower grounds is between about one andone-quarter feet and about two feet.

The plurality of electrical stimulation probes 428 and 434 are providedextending away from the left side frame 420 and the right side frame422, respectively. That is, the plurality of electrical stimulationprobes 428 and 434 extend into the animal carcass traveling path 423.Accordingly, as the animal carcass 410 moves through the animal carcasstraveling path 423, the animal carcass 410 contacts each of theplurality of electrical stimulation probes 428 and 434. The contactbetween the animal carcass 410 and each of the electrical stimulationprobes is for a period of time which varies depending upon the speed ofthe animal carcass 410 along the animal carcass traveling path 423, thelength of each electrical stimulation probe, and the size of the animalcarcass.

The plurality of electrical stimulation probes 428 includes electricalstimulation bars 450 which extend into the animal carcass traveling path423. Preferably, the electrical stimulation bars 450 generally extend atan angle of between about 50 degrees and about 130 degrees from an axisextending along the animal carcass traveling path 423 that is expectedto be along the length of the electrical stimulation frame 412.Preferably, the electrical stimulation bars 450 are providedperpendicular to the line of travel through the animal carcass travelingpath 423. The electrical stimulation bars 450 are preferably provided sothey bend allowing the animal carcass 410 to move through the animalcarcass traveling path 423. As the animal carcass 410 moves along theanimal carcass traveling path 442, each electrical stimulation bar orrod 450 sequentially contacts the exterior surface 452 of the animalcarcass and maintains contact with the exterior surface 452 until theanimal carcass 410 moves beyond the contact length 454 of the electricalstimulation probes 450. Rather than provide electrical stimulation bars450 which bend, the electrical stimulation bars 450 can be provided on aspring which allows the electrical stimulation bars 450 to remainrelatively rigid while moving out of the way of the animal carcass andmaintaining contact with the animal carcass surface 452.

The electrical stimulation frame 412 includes a left side frame 420 anda right side frame 422 to conveniently process both left and right sidesof carcasses. In general, it is desirable to maximize the contact areabetween each electrical stimulation probe and the animal carcass.Depending upon whether the animal carcass moving along the animalcarcass traveling path 423 is a left side or a right side, either theelectrical stimulation probes 428 or the electrical stimulation probes434 will maintain better contact. The plurality of electricalstimulation probes 428 maintains better electrical contact with theanimal carcass 410 when the carcass is a left side carcass (dorsal sidefirst). The plurality of electrical stimulation probes 434 maintainsbetter electrical contact with the animal carcass when the carcass is aright side carcass (dorsal side first).

The animal carcass 410 is preferably moved through the electricalstimulation frame 412 dorsal side first from the inlet 414 to the outlet416. The applicants have found that by moving the animal carcass 410dorsal side first, it is possible to provide better contact between theplurality of electrical stimulation probes 428 and 434 and the animalcarcass surface 452 closest to the muscles targeted for electricalstimulation.

The electrical stimulation probes 428 and 434 are held in place on theelectrical stimulation frame 412 by receivers 456. The receivers 456insulate the electrical stimulation probes 428 and 434 from the uppergrounds 424 and 430 and the lower grounds 426 and 432. Furthermore, theelectrical stimulation frame 412 includes insulating rails 458 and 460that are held in place by rail holders 462. In general, it is desirableto avoid short circuiting the operation of the electrical stimulationframe 412 by contact of the animal carcass with any other grounding partof the frame than the upper grounds 424 and 430 and the lower grounds426 and 434. Accordingly, the insulating rails 458 and 460 are providedso that the animal carcass does not create a short circuit between theelectrical stimulation probes 428 and 434 and the bars 464 and 466 alongwhich the electrical stimulation probe holders 456 are placed.

A power source 470 is provided for providing electrical stimulation tothe electrical stimulation probes 428 and 434 along line 472, and to theground along line 474.

The plurality of electrical stimulation probes 428 and 434 arepreferably constructed to provide periods of electrical stimulation andperiods of no electrical stimulation as the animal carcass 410 movesthrough the electrical stimulation frame 412. The applicants have foundthat it is desirable to include rest intervals where there are noelectrical stimulations so that the targeted muscles can relax betweenperiods of electrical stimulation. In general, it is desirable for therest interval to be sufficient so that the animal carcass regains atleast about 90% of its original length. During the electricalstimulation, the animal carcass can shorten in its original length byalmost 40%. Much of this shortening is the result of the musclescontracting and the vertebrae curving. The applicants believe that thefollowing formulae represent the desired relationship between thevoltage for electrical stimulation, the time of electrical stimulation,and the time of interval between electrical stimulations:

 T _(stim)=60×D _(cl) /V _(cs)

T _(rest)=60×(D _(ww) −D _(cl))/V _(cs)

In the above formulae, T_(stim) refers to time of stimulation, T_(rest)refers to time of rest between stimulations, V_(cs) refers to chainspeed conveying the carcass through the stimulation frame, D_(ww) refersto the contact point spacing (distance between electrical stimulationprobes), and D_(cl) refers to contact length (distance in which theelectrical stimulation probe is in contact with the carcass). For aV_(cs) of 42 feet/min., a D_(ww) of three feet, and a D_(cl) of twofeet, the T_(stim) is about 2.9 seconds and the T_(rest) is about 1.4seconds.

It is generally desirable to provide an electrical stimulation protocolthat provides the desired level of stimulation in the targeted musclesof an animal carcass while minimizing floor space dedicated to providingelectrical stimulation in an animal processing facility. In general, itis desirable to implement the electrical stimulation protocol until,under observation, it appears that the reaction by the animal carcass tothe electrical stimulation is significantly decreased or that the animalcarcass does not react any further to the electrical stimulation. It isbelieved that the electrical stimulation causes a contraction in themuscles that corresponds to a working of the muscles. It is believedthat as the energy in the muscle is depleted by the working of themuscle, the muscle reaches a further electrical stimulation will notgenerate a substantially observable amount of contraction.

The electrical stimulation protocol can be maintained for at least aboutthirty seconds in order to deplete the targeted muscles. Preferably, theelectrical stimulation protocol is conducted by multiple periods ofelectrical stimulation. The electrical stimulation protocol can beprovided with either alternating current or direct current. Preferably,the electrical stimulation protocol utilizes alternating current. Inaddition, the voltage is preferably sufficiently high so that a desiredpercentage of muscle fibers in the targeted muscles are recruited(contracted). In general, it is desirable for all of the muscle fibersto be recruited. It is expected that once all the muscle fibers arerecruited, additional voltage causes heating of the muscle that can bedetrimental to the carcass. In general, it is preferable to have thevoltage between about 40V and about 500V. In the case of alternatingcurrent, it is desirable to have a frequency of between about 40 Hz andabout 60 Hz.

The electrical stimulation protocol preferably includes alternatingperiods of stimulation and rest. Preferably, the periods of stimulationare for between about one second and about five seconds, and morepreferably between about 2 seconds and about 3 seconds. Preferably, theperiods of rest are between about 0.5 seconds and about three seconds. Apreferred electrical stimulation protocol can be conducted for sixtyseconds including alternating periods of two seconds of electricalstimulation and one second of rest. In such an electrical stimulationprotocol, it is believed that each of the electrical stimulation probeswould provide a period of electrical stimulation and the period betweeneach electrical stimulation probe would provide the period of rest. Inaddition, such an electrical stimulation protocol could be accomplishedby arranging two of the electrical stimulation frames 412 in series toprovide eighteen periods of electrical stimulation.

It is expected that each period of stimulation will be created by thecontact of a single electrical stimulation probe with the surface of theanimal carcass. Accordingly, the length of contact between the surfaceof the animal carcass and the electrical stimulation probe, at aparticular animal carcass traveling speed, will result in a particularelectrical stimulation contact time. It is expected that the contactlength of the electrical stimulation probe (the length of the probe thatcontacts and provides electrical stimulation to the surface of theanimal carcass) is between about one foot and about three feet, and morepreferably between about 1½ feet and about 2½ feet.

When the animal carcass 410 being processed through the electricalstimulation frame 412 is a bovine carcass, it is generally preferablythat the upper grounds 424 and 430 contact the carcass 410 in thegeneral region of the fifth and sixth sacral vertebrae, and that thelower grounds 426 and 432 contact the carcass 410 in the general regionof the fifth and sixth thoracic vertebrae. In addition, it is generallydesirable for the plurality of electrical stimulation probes 428 and 434to contact the carcass 410 in the general region between the elevenththoracic vertebra and the second lumbar vertebra. By contacting theanimal carcass 410 with the grounds and electrical stimulation probes atthese locations, it is believed that the electrical stimulation can betargeted in the carcass midsection which generally includes the thinnermuscles of the rib and loin which are generally characterized asextending from about between the fifth and sixth thoracic vertebrae andabout between the fourth and fifth sacral vertebrae. It is generallydesirable to minimize electrical current stimulation in the chuck andround muscles to allow the chuck and round muscles to cool to a desiredtemperature prior to the onset rigor mortis. Accordingly, the electricalstimulation apparatus according to the invention preferably focuses theelectrical stimulation within the midsection.

It should be understood that the subject matter of U.S. ProvisionalApplication Ser. No. 60/178,836, filed on Jan. 28, 2000, is incorporatedherein by reference.

What is claimed:
 1. A method for processing an animal carcasscomprising: (a) providing an animal carcass having a midsection andanterior and posterior end sections, the anterior and posterior endsections having muscles that are thicker than muscles provided in themidsection; (b) focusing electric current along the animal carcassmidsection to provide an animal carcass having electrically stimulatedmuscles in the midsection and non-electrically stimulated muscles in theanterior and posterior end sections.
 2. A method for processing ananimal carcass according to claim 1, wherein said animal carcasscomprises a bovine carcass.
 3. A method for processing an animal carcassaccording to claim 1, wherein the midsection of said animal carcassincludes rib section and loin.
 4. A method for processing an animalcarcass according to claim 1, wherein the anterior end section includeschuck, and the posterior end section includes round.
 5. A method forprocessing an animal carcass according to claim 1, wherein said step ofapplying an electric current comprises attaching a positive probe andtwo negative probes to the midsection of said animal carcass.
 6. Amethod for processing an animal carcass according to claim 5, whereinthe positive probe is placed in the vicinity of the 5^(th) and 6^(th)lumbar vertebrae and the ground probes are placed in the vicinity of the4^(th) and 5^(th) sacral vertebrae and the 5^(th) and 6^(th) thoracicvertebrae.
 7. A method for processing an animal carcass according toclaim 1, further comprising a step of: (a) cooling the animal carcasshaving an electrically stimulated midsection and non-electricallystimulated first and second end sections to provide an internal muscletemperature in the first and second end sections of less than about 70°F. before onset of rigor.
 8. A method for processing an animal carcassaccording to claim 1, further comprising a step of: (a) cooling saidanimal carcass having an electrically stimulated midsection andnon-electrically stimulated first and section end section to provideinternal muscle temperature in the first and second end sections of lessthan about 40° F. within 48 hours after slaughter.
 9. A method forprocessing an animal carcass according to claim 1, wherein animalcarcass is a bovine carcass, and the midsection includes inner musclesprovided from about between the fifth and sixth thoracic vertebrae andabout between the fourth and fifth sacral vertebrae.
 10. An apparatusfor applying electrical stimulation to an animal carcass comprising: a)an elongated electrical stimulation bar having a first and second ends,said first end having a sharp point for insertion into the animalcarcass; b) a first elongated ground bar having a first and second ends,said first end having a sharp point for insertion into said carcass,said second end electrically connected to ground; c) a second elongatedground bar having a first and second ends, said first end having a sharppoint for insertion into said carcass and said second end electricallyconnected to ground; d) an electrical impulse generating circuitelectrically connected to said elongated electrical stimulation bar;wherein said elongated electrical stimulation bar and said first andsecond elongated ground bars provide for isolation of the electricalstimulation to the animal carcass to between said elongated electricalstimulation bar and said first elongated ground bar and between saidelongated electrical stimulation bar and said second elongated groundbar.
 11. An electrical stimulation apparatus comprising: (a) anelectrical stimulation frame having an inlet, an outlet, and a lengthextending between the inlet and the outlet, the frame being constructedfor allowing an animal carcass to pass from the inlet to the outlet andfor providing electrical stimulation to the animal carcass as it passesfrom the inlet to the outlet; (b) the electrical stimulation frameincluding: (i) a plurality of electrical stimulation probes providedalong the length of the frame for contacting the animal carcass as itpasses between the inlet and the outlet; (ii) an upper ground extendingalong the length of the frame above the plurality of electricalstimulation probes and being provided for contacting the animal carcass;and (iii) a lower ground extending along the length of the frame andbelow the plurality of electrical stimulation probes and being providedfor contacting the animal carcass.
 12. An electrical stimulationapparatus according to claim 11, wherein the electrical stimulationframe includes a left side frame and a right side frame wherein: (a) theleft side frame comprising: (i) a first plurality of electricalstimulation probes comprising said plurality of electrical stimulationprobes; (ii) a first upper ground comprising said upper ground; (iii) afirst lower ground comprising said lower ground; and (b) the right sideframe has an inlet and outlet and a length extending between the inletand the outlet, the right side frame comprising: (i) a second pluralityof electrical stimulation probes provided along the length of the rightside frame for contacting the animal carcass as it passes from the inletto the outlet; (ii) a second upper ground extending along the length ofthe frame above the second plurality of electrical stimulation probesand being provided for contacting the animal carcass; and (iii) a secondlower ground extending along the length of the frame below the secondplurality of electrical stimulation probes and being provided forcontacting the animal carcass.
 13. An electrical stimulation apparatusaccording to claim 11, further comprising: (a) a conveyor for conveyingthe animal carcass from the inlet to the outlet.
 14. An electricalstimulation apparatus according to claim 13, wherein the conveyorcomprises a rail and a trolley that moves along the rail, and thetrolley includes a hanger for holding the animal carcass.
 15. Anelectrical stimulation apparatus according to claim 12, wherein theelectrical stimulation frame includes a carcass traveling path providedbetween the left side frame and the right side frame and extending fromthe inlet to the outlet.
 16. An electrical stimulation apparatusaccording to claim 15, wherein the width of the carcass traveling pathextending between the first upper ground and the second upper ground isbetween about one foot and about five feet.
 17. An electricalstimulation apparatus according to claim 15, wherein the width of thecarcass traveling path between the first lower ground and the secondlower ground is between about one foot and about five feet.
 18. Anelectrical stimulation apparatus according to claim 11, wherein thevertical distance between the plurality of electrical stimulation probesand the upper ground is between about one foot and about two feet. 19.An electrical stimulation apparatus according to claim 11, wherein thevertical distance between the plurality of electrical stimulation probesand the lower ground is between about one foot and about two feet. 20.An electrical stimulation apparatus according to claim 11, wherein: (a)the plurality of electrical stimulation probes, the upper ground, andthe lower ground are positioned so that, for a bovine carcass hangingfrom its posterior end and moving along the length of the, electricalstimulation frame from the inlet to the outlet: (i) the plurality ofelectrical stimulation probes contact the surface of the carcass at alocation corresponding to about the eleventh thoracic vertebrae to aboutthe second lumbar vertebrae; (ii) the upper ground contacts the surfaceof the carcass at a location corresponding to about the fourth sacralvertebrae to about the fifth sacral vertebrae; (iii) the lower groundcontacts the surface of the carcass at a location corresponding to aboutthe fifth thoracic vertebrae and the sixth thoracic vertebrae.
 21. Anelectrical stimulation apparatus according to claim 11, furthercomprising: (a) a power source for providing an electrical potentialbetween the plurality of electrical stimulation probes and the upperground and lower ground.
 22. An electrical stimulation apparatusaccording to claim 11, wherein said plurality of electrical stimulationprobes are provided extending away from the electrical stimulation frameand into a path the animal carcass moves through traveling from theinlet to the outlet.
 23. An electrical stimulation apparatus accordingto claim 22, wherein the plurality of electrical stimulation probes havea contact length of between about one foot and about three feet.
 24. Anelectrical stimulation apparatus according to claim 22, wherein theplurality of electrical stimulation probes are provided extendingbetween about 50 degrees and about 130 degrees away from an axisextending along the length of the electrical stimulation frame.
 25. Amethod for electrically stimulating an animal carcass, the methodcomprising steps of: (a) moving an animal carcass along a length of anelectrical stimulation frame from an inlet to an outlet, wherein theelectrical stimulation frame includes: (i) a plurality of electricalstimulation probes provided along the length of the frame for contactingthe animal carcass as it passes from the inlet and the outlet; (ii) anupper ground extending along the length of the frame above the pluralityof electrical stimulation probes and being provided for contacting theanimal carcass; (iii) a lower ground extending along the length of theframe below the plurality of electrical stimulation probes and beingprovided for contacting the animal carcass.
 26. A method according toclaim 25, further comprising a step of: (a) electrically stimulating theanimal carcass.
 27. A method according to claim 25, wherein the step ofmoving an animal carcass along a length of an electrical stimulationapparatus comprises moving the animal carcass dorsal side first.
 28. Amethod according to claim 25, wherein the animal carcass comprises aside of an animal carcass that has been split along a backbone.